Core Java学习2（基础知识）

Chapter 3. Fundamental Programming Structures in Java
1．前言
20日上班较忙，晚上也没空，21日晚上，看了看MIT的公开课，计算机导论，外语，听不太懂，得看字幕，老外挺有意思的，其中讲到了没有最好的编程语言，只有最适合的，所以编程语言只是工具，最主要是你要干什么，该课要求用python因为流行且简单。我想干什么，我想整点手机应用android平台，学java应该是没错吧。（补充一下，看老外的视频，最后还是睡着了，一是听力跟不上，第二绝对不能在床上，最好还是书桌上，想睡也没这么方便）

There are eight primitive types in Java. Four of them are integer types; two are floating-point number types; one is the character type char, used for code units in the Unicode encoding scheme; and one is a boolean type for truth values.
Type Storage Requirement Range (Inclusive)
Int 4 bytes –2,147,483,648 to 2,147,483, 647 (just over 2 billion)
Short 2 bytes –32,768 to 32,767
Long 8 bytes –9,223,372,036,854,775,808 to 9,223,372,036,854,775,807
Byte 1 byte –128 to 127

float 4 bytes approximately ±3.40282347E+38F (6–7 significant decimal digits)
double 8 bytes approximately ±1.79769313486231570E+308 (15 significant decimal digits)

All floating-point computations follow the IEEE 754 specification. In particular, there are three special floating-point values:
• positive infinity
• negative infinity
• NaN (not a number)
If you need precise numerical computations without roundoff errors, use the BigDecimal class   

Constants
In Java, you use the keyword final to denote a constant.

                                                                Corydon
                                                                                        2012-6-22